Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates generally to clamp assemblies for connecting one member to a support member, and more particularly to a high strength buoyant clamp assembly to attach a pipe or line, such as an umbilical line, to another pipe, and shields the pipe and line from contact with each other and surrounding media. The present invention is particularly adapted for use as a subsea clamp assembly to attach an umbilical line to any type of subsea riser pipe or wireline.
2. Description of the Related Art
The need often arises for a clamp assembly to attach a cable, hose, or pipe to a support member or pipe. Typically, the cable, hose, or pipe is run along the length of the support member or pipe. Many types of clamp assemblies have been used to secure the members to one another. The members may be horizontally positioned or vertically positioned. It is generally desirable that the clamp assembly be capable of quick installation while securely attaching the clamped members to one another. Additionally, it is desirable that the clamp assembly be lightweight and relatively inexpensive.
In the offshore drilling and production industry, it is frequently necessary to run umbilical lines hundreds and even thousands of feet below the support vessel or drilling or production platform down to the sea floor and possibly beyond. Typically, the umbilical lines, which may include electric, MUX (fiber optics), and hydraulics, are required to be attached to a support member, such as a choke or kill line for workover/completion risers, or mud line on a subsea riser system. Due to the high cost of working in such environments, it is critical that the clamp assembly be easy to install, quickly installed, reliable, durable, and dependable to firmly secure the clamped members. Failure of a clamp during drilling can cause unnecessary expense as broken pieces of the clamp assembly may descend into the well, thereby clogging or jamming the lines and other essential equipment during the drilling process. Fishing for broken clamp assembly pieces in a well can be time consuming and result in increased drilling and production delays. Thus, a buoyant clamp assembly would eliminate the likelihood of clamp failure interfering with the drilling process. During the drilling process, the clamp assembly is subjected to significant jarring and contact with the inside of the well casing. Thus, the clamp must be strong enough to withstand constant striking and jolting against the inner casing. In the offshore industry, limited platform space is available for the workman to install the clamp assemblies and sometimes the workman is limited to accessing the riser from a single side. Thus, it is vitally important that the clamp assembly be easy to install from a location on both sides or sometimes one side of the riser.
In the past, riser clamps comprised of two half sections joined about the riser have been used. Typically, these riser clamps were fabricated completely from steel or stainless steel. Such clamps were subject to rust and corrosion and added unwanted weight to the entire clamped assembly causing an increased risk of assembly parts interfering with the drilling process in the event of a failure. Additionally, such clamps tended to be time consuming to install. Another type of riser clamp that has been used is similar to a large hose clamp which screws tight and directly clamps the clamped members to the support member. This type of clamp is subject to damaging the clamped members and is time consuming to install, and does not accommodate size variances of the umbilical(s). Not being able to accommodate size variances can have disastrous consequences if the umbilical hose slips downward and loops inside the marine drill riser or in open water. A MUX line loses its signal transmission if a loop results because of poor clamping. Still other types of prior art clamps have bodies molded of urethane. Typically, a mold relief substance penetrates the skin of the urethane-molded bodies during the molding process and results in the body surface having very low frictional capabilities. It is not desirable to have low frictional capabilities between the clamp body and the riser and/or umbilical members.
Applicant""s U.S. Pat. No. 5,598,995 to Meuth discloses a clamp assembly having a receptacle adapted to at least partially receive an elongate member, a pair of flexible support straps connected to the receptacle, and a pair of flexible clamping straps. The pair of flexible support straps are capable of matingly engaging one another around a support member and the pair of flexible clamping straps are capable of matingly engaging one another around one or more elongate members and the support member. The receptacle includes a receptacle body made of high density polyurethane foam having a recess therein adapted to at least partially receive the elongate member. A pivotable buckle is attached to one of the flexible clamping straps for securely tensioning the pair of clamping straps around the elongate member or members and the support member. An adjustment assembly is attached to one of the flexible clamping straps. The adjustment assembly comprises an elastomeric adjuster attached to one of the flexible clamping straps and an adjustment patch attached to the elastomeric adjuster. The adjustment patch is capable of matingly engaging one of the flexible clamping straps. The pairs of flexible support straps and flexible clamping straps engage with hook and loop type fasteners.
Applicant""s U.S. Pat. No. 5,921,517 to Meuth discloses a clamp assembly for clamping an elongate member to a support member. The clamp assembly includes a flexible strap having first and second ends. The flexible strap extends substantially around the elongate and support members. The first and second ends are adapted to be coupled to each other or to the support member. The clamp assembly also includes a tensioner assembly having first and second tensioner bars spaced parallel to one another. Each of the first and second tensioner bars includes a bullnose face and the bullnose faces are in opposing relationship to one another. The tensioner assembly also includes an adjusting member for adjusting the spacing between the first and second tensioner bars. The flexible strap extends twice through the space between the first and second tensioner bars.
It is desirable to have a high strength clamp assembly that is lightweight and buoyant, easy to install, capable of being quickly installed, and able to withstand jarring contact with the inner well casing and protect the lines or pipes. It is also desirable that the high strength buoyant clamp assembly be economical and durable, in addition to firmly securing an elongate member to a support member. The clamp assembly should also provide protection against abrasion at the contact points with the clamped members.
The present invention is a high strength buoyant clamp assembly and method utilizing a flexible strap and a friction multiplier material to securely clamp an elongate member to a support member. The high strength clamp assembly is lightweight and buoyant, easy to install, capable of quick installation, and exceptionally durable by design to protect the lines or pipes from contact with each other and an inner well casing. The high strength clamp assembly is economical and firmly secures the clamped members to one another, and accommodates all variances of size for both the umbilical(s) and riser pipe(s) being clamped together.
The high strength buoyant clamp assembly includes a flexible strap having first and second ends. The flexible strap extends substantially around the elongate and support members. Affixed to the first end of the flexible strap is a pull tab which is adapted to be passed through an elongate loop affixed to the second end of the flexible strap. The flexible strap is secured by a tensioner assembly. Affixed to the exterior of the flexible strap are spaced buoyant wear blocks. Stitched to the interior of the flexible strap is a friction multiplier to improve the gripping of the elongate and support members. The tensioner assembly includes first and second tensioner bars spaced parallel to one another and attached to each other by buoyant capture bars. Each of the first and second tensioner bars includes a bullnose face and the bullnose faces are in opposing relationship to one another. The tensioner assembly also includes a pair of threaded adjusting members for adjusting the spacing between the first and second tensioner bars. In use, the first and second tensioner bars are situated substantially between the elongate member and the support member.